1. Field of the Invention
The present invention relates to a conduction cooling superconducting magnet device.
2. Description of the Background Art
Japanese Patent Laying-Open No. 11-340028 and Japanese Patent Laying-Open No. 2000-182821 each disclose a conduction cooling superconducting magnet device including a pipe through which a coolant flows, in addition to a refrigerator, in order to reduce initial cooling time.
The superconducting magnet device described in Japanese Patent Laying-Open No. 11-340028 includes a cooling pipe having opposite end portions drawn out of a vacuum chamber and an intermediate portion in thermal contact with a superconducting coil. The cooling pipe includes a first shield-penetrating portion penetrating a radiation shield in a thermal non-contact state, and a second shield-penetrating portion penetrating the radiation shield in a thermal contact state.
The superconducting magnet device described in Japanese Patent Laying-Open No. 2000-182821 includes a coolant repository provided in a radiation shield, and a coolant supply pipe and a coolant discharge pipe in communication with a coolant supply system and a coolant discharge system provided outside a vacuum chamber, respectively. The coolant repository is thermally connected to a superconducting coil directly or via a thermal conduction member.
With a pipe through which a coolant flows being in contact with a superconducting coil as described above, the superconducting coil can be cooled in a short time by a refrigerator and the coolant flowing through the pipe.
A conduction cooling superconducting magnet device includes a provided member penetrating or being in contact with a radiation shield while penetrating or being in contact with a vacuum chamber in contact with the outside. Such provided member conducts external heat from the vacuum chamber to the radiation shield, and has thus been a factor preventing cooling inside the radiation shield.